The present invention relates generally to plate-making method and plate-making apparatus for the printing original plate, and more particularly to a plate-making method and plate-making apparatus arranged to use a photosensitive resin denatured or hardened in response to ultraviolet light.
Generally, for relief printing technique is known a technique in which, with a negative or positive film being used as a mask, an etching-proof thin-film is formed by light illumination using a photo-resist to effect a partial etching of a metal (for example) or a relief is produced using a photosensitive resin of the type that is undissolved by light illumination. There are problems which arise with such a plate-making technique, however, in that it is required to produce a transmission-type film to be used as a mask and further to produce three kinds of plates, i.e., Y (yellow), M (magenta) and C (cyan), for the color original printing. In addition, ultraviolet light required for exposing the photosensitive resin and hence difficulty is encountered to produce the three kinds plates color-distributed from the color original.